I had a flock of 20 Dominque chickens (10 roo's & 10 hens) about 5 months old, they are dying suddenly ( healthy today & gone the next morning.) I have checked them over and eyes are clear, no slime in the mouth, or apparent respiratory issue. They appear healthy /fat just suddenly can't hold their head up. Any assistance would be greatly appreciated. I have cleaned , sanitized the pen but am still losing them.
That sounds like heatstroke or dehydration. Get some poultry vitamins with electrolytes(SaveAChick, Rooster Booster, Durvet) to add to the water. Get a flat pig pan or small plastic pool, put it in the shade, and add water to about 3-4 inches so they can cool their legs off. I f any look lethargic, place them in cool, not cold water, and give them electrolyte water with a dropper. Look for diarrhea, not eating, lethargy, or other signs of coccidosis, which is best treated with Corid.
Sorry to hear about that. I'm certainly no expert and the only issue I've had to deal with so far was heat stroke with Cornish Crosses, but the symptoms sound about like yours. What's the high temps where you're at?
I would treat for coccidia with Sulmet or Corid. Years ago I had guineas do same thing at about same age. Coccidia has it's entire life cycle within bird, unlike worms that have to pass through intermediaries. So, bird can ingest single oocyte and have full scale outbreak in three weeks. Keeping all too clean actually not good because when birds exposed they are overwhelmed. At about this age I also learned a good idea to deworm, check for lice/mites, too.
